The production of can ends, and notably can ends having easy-opening features thereon, for use on beverage containers for, for example, soft drinks and beer, is a multi-stage operation. Metal sheet, typically formed from an aluminum or steel alloy, is fed to a blanking press, where circular blanks are cut from the sheet and shaped between a pair of dies into flush panel ends.
These flush panel ends are then passed to a curler, which forms a flange around the outer edge thereof to enable the end to be sealed to a can body by the commonly-accepted double seaming operation.
Finally, the flush panel ends are fed to a conversion press. In this press, the ends pass between a series of pairs of forming dies, which dies produce the easy-opening feature. Included in this conversion operation are scoring, rivet forming and tab staking. The finished ends exiting from the conversion press are then ready for packaging and sale.
Initially, either the relatively low speeds of the equipment involved were fairly well matched or economics permitted manual handling of the ends between stations.
More recently, however, increased labor costs and improvements in can end manufacturing equipment have dictated a need for a fully mechanized can end forming system with reduced manning levels and virtual elimination of manual handling of the ends from their initial stamping to their completion.
A major problem in accomplishing full mechanization in a can end line is in the speed differentials or, more accurately, the throughput differentials, between portions of the system. Advances in blanking press speed have increased the number of ends which can be produced per die lane in a given amount of time. Additionally, advances in blanking press size have allowed multiple lane dies to become a commercial reality. It is thus not uncommon for a single large end forming press to out perform two or even three older model presses.
Concurrently, advances in curling equipment, including the use of double lane curlers, have enabled this portion of the system to keep up with the end blanking presses.
The bottleneck, however, resides in the conversion press. Requiring multiple stations, in-feed and placement of tabs onto the ends, and intricate die tooling, these presses operate at speeds far less than those of end blanking presses. While multiple lane end conversion presses are known, the need for either multiple conversion presses or a multiple lane conversion press requires that the ends be divided into separate lanes somewhere between the curler and the conversion press.
Typically, this has been a manual operation. An operator stationed between the curler and the conversion press manually removes a stick containing, for example, 400 or so ends at a time from the exit lane of the curler and alternately feeds these ends into the entrance lanes of either separate conversion presses or separate lanes of a multi-lane conversion press, bagging excess ends created in the blanking portion of the system above the number of ends that can be handled in a given amount of time by the conversion portion of the system. To completely automate the system, there is a need, therefore, for an apparatus capable of reliably dividing a supply of can ends from a single stick or lane into a pair of can end lanes. The apparatus must also be capable of adjusting or otherwise accounting for speed variations between the somewhat faster blanking portion of the system and the somewhat slower conversion portion of the system, so that any excess flush panel ends can be diverted to a temporary storage area.